According to the report, he will use the investment to build "a nationwide grass-roots network to motivate voters who feel strongly about curbing gun violence." Peters wrote that Bloomberg "tossed out the $50 million figure out as if he were describing the tip he left on a restaurant check" and hinted he could spend even more in his battle against the NRA.

“I put $50 million this year, last year into coal, $53 million into oceans,” Bloomberg said referencing money he's spent on environmental initiatives. “Certainly a number like that, $50 million. Let’s see what happens.”

The NRA did not immediately respond to a request for comment about Bloomberg's plans.

Bloomberg also dismissed the idea his reputation as the "nanny" mayor of a big city who has pushed bans on smoking and sugary drinks in addition to gun control might not make him the ideal face of a gun control campaign that will need to change hearts and minds in red states.

“I don’t know what your perception is of our reputation, and mine, the name Bloomberg around the country,” he said noting that in his travels he regularly hears people tell him, “You’re a rock star" and "people yelling out of cabs, ‘Hey, way to go!’”

Under his plan, Bloomberg would bring two gun-focused groups he currently funds — Mayors Against Illegal Guns and Moms Demand Action for Gun Sense in America — under one umbrella group called Everytown for Gun Safety. It will focus in the short term on legislation to expand background checks on gun buyers.

The group's focus will be on field operations, something the NRA and other pro-gun groups have mastered. The focus of their outreach will be on women — mothers, in particular — who they feel can be swayed on the gun issue.

The topic of gun violence has largely faded from the national scene. It has been almost a year since the Senate failed to pass a bill that would have expanded background checks, and there has been no renewed momentum. That defeat was widely seen as a loss for Bloomberg, who spent over $10 million on his gun control campaign prior to the bill's failure. Supporters tout progress on the background check issue at the state level.

Some groups hinted at plans to punish senators who voted against the background check bill last year. When they did, some Democrats and liberals argued it would be counterproductive, since pushing red-state Democrats to the left on gun issues could lose the party the Senate.

Bloomberg doesn't seem to care about causing difficulties for Democrats, saying his focus is squarely on the gun fight.

“You can tell me all you want that the Republicans would be worse in the Senate than the Democrats,” he said. “Maybe they would. But that’s not what we’re talking about here.”